The former Marine and Douglas resident will run against the winner of the August Republican primary, either incubent Congressman Fred Upton or former state senator Jack Hoogendyk.

In a press release from the Kalamazoo County Democratic Party, O'Brien discussed why he is running (read it here).

“I felt I had a debt to repay, and that service to others in the defense of our nation was a noble calling," O'Brien said in the release. "I rose through the ranks, and served with pride and distinction as a Reconnaissance Marine, always mindful of the honor of serving one’s nation."